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Dependences in the pillar 'Earth's gravity field' of GGOS - description using UML notation

Paśnicka M., Szafranek K., Zwirowicz-Rutkowska A.

Reports on Geodesy

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2012

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z. 1/92

135--142

EN

Earth’s gravity field is one of three pillars of the Global Geodetic Observing System (GGOS). Gravity measurements are made using both classical methods by the means of ground measurement facilities (relative and absolute gravimetry) and methods based on the satellite techniques (SLR, missions CHAMP, GRACE, GOCE) or airborne gravimetry. The main objective of this GGOS pillar is to determine geoid’s shape, Earth’s static gravitational potential and temporal variations induced by solid Earth processes and mass transport in the global water cycle. The paper presents relationships between the main classes of diagrams of the Earth’s gravity field described using UML (Unified Modelling Language). Such description can be helpful in the analysis of the gravitational field pillar linkages with other pillars of GGOS. The main purpose of this paper is to give the full explanation of connections between all Earth’s gravity field GGOS components. Key words: Earth’s gravity field, UML, GGOS.

2

Geokinematics in GGOS - different relations and dependences

Pachelski W., Paśnicka M., Szafranek K., Zwirowicz-Rutkowska A.

Artificial Satellites : Journal of Planetary Geodesy

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2011

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Vol. 46, No. 1

9--17

EN

The paper presents the preliminary results of the analysis of fundamental dependencies between different geodetic concepts related to the one of the GGOS (Global Geodetic Observation System) pillars called Geometry and Kinematics. These relationships are described using UML (Unified Modelling Language) – one of the graphical notations that can be used for information modelling. Concepts are represented as classes with their names, attributes, and different kinds of links between them. The main purpose of this paper is to introduce the full description of connections between all GGOS components.

3

Comparison of the geophysical excitations of polar motion from the period: 1980.0-2009.0

Nastula J., Paśnicka M., Kołaczek B.

Acta Geophysica

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2011

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Vol. 59, no. 3

561-577

EN

In this study we compared contributions to polar motion excitation determined separately from each of three kinds of geophysical data: atmospheric pressure, equivalent water height estimated from hydrological models, and harmonic coefficients of the Earth gravity field obtained from Gravity Recovery and Climate Experiment (GRACE). Hydrological excitation function (Hydrological Angular Momentum - HAM) has been estimated from models of global hydrology, based on the observed distribution of surface water, snow, ice, and soil moisture. In our consideration we used several global models of land hydrosphere and models of Atmospheric Angular Momentum (AAM) and Oceanic Angular Momentum (OAM). All of them were compared with observed Geodetic Angular Momentum (GAM). The spectra of the following excitation functions of polar motion: GAM, AAM+OAM, AAM+OAM+HAM, GAM-AAM-OAM residual geodetic excitation function, and HAM were computed too. The time variable spectra of geodetic, gravimetric, and the sum of atmospheric, oceanic, and hydrological excitation functions are also presented. Phasor diagrams of the seasonal components of polar motion excitation functions of all HAM excitation functions as well as of two GRACE solutions: Center for Space Research (CSR), Centre National d'Etudes Spatiales/Groupe de Recherche en Geodesie Spatiale (CNES/GRGS) were determined and discussed.